MAI 


oar_i£L^f'° 


0  |  UNITED  STATES  FUEL  ADMINISTRATION 

0  Hfi|  BUREAU  OF  CONSERVATION 

o  |  Engineering  Bulletin  No.  1 


BOILER  and  FURNACE 
TESTING 


Prepared  by 

Rufiis  T.  Strohm 

Associate  Editor,  Power 


Maximum  Production 


WASHINGTON 
GOVERNMENT  PRINTING  OFFICE 

1918 


MAXIMUM  PRODUCTION. 
MINIMUM  WASTE, 

The  United  States  Fuel  Administration  is  making  every  effort,  through  the  pro- 
ducers and  transportation  lines,  to  obtain  an  adequate  supply  of  fuel  for  the  industries 
of  the  country. 

Twenty-five  to  fifty  million  tons  of  coal  a  year  can  be  saved  by  the  improved  oper- 
ation of  steam-power  plants  without  changing  their  present  equipment  and  without 
abating  their  production  the  slightest. 

It  is  absolutely  necessary  that  this  saving  be  realized,  if  our  overburdened  railroads 
are  to  be  relieved  and  our  industries  kept  in  full  operation. 

The  extent  to  which  it  will  be  realized  depends  upon  the  cooperation  of  the  own- 
ers, engineers,  and  firemen  of  every  power  plant  of  the  country. 

YOUR  FIRING  LINE  IS  AT  THE  FURNACE  DOOR. 

David  Moffat  Myers, 
Advisory  Engineer  to  United  States  Fuel  Administration. 


BOILER  AND  FURNACE  TESTING. 

By  Rufus  T.  Strohm. 


NECESSITY  FOR  TESTING  BOILERS. 

A  boiler  test  is  necessary  in  order  to  determin  3  now  well  the  boiler 
is  doing  the  work  expected  of  it;  that  is  to  say,  we  must  find  out 
whether  we  are  wasting  coal  in  making  steam  and  how  much  this 
waste  may  be.  Such  a  test  may  be  made  to  discover  the  efficiency 
of  the  boiler,  or  the  quantity  of  water  it  is  evaporating,  or  the  cost 
of  evaporating  1 ,000  pounds  of  water. 

The  United  States  Fuel  Administration  recommends  that  every 
boiler  plant  have  some  means  of  daily  checking  the  efficiency  of  the 
boiler  and  furnace.  The  simplest  and  best  way  of  finding  out  how 
efficiently  the  boiler  is  working  is  to  make  an  evaporation  test,  as 
described  in  this  bulletin.  All  the  necessary  records  can  be  made 
automatically  with  suitable  instruments,  although  in.  many  small 
plants  the  coal  must  be  weighed  on  ordinary  scales.  The  efficiency 
of  the  furnace  can  be  found  by  making  analyses  of  the  flue  gases. 
(See  Bulletin  No.  2  of  the  United  States  Fuel  Administration.) 

Too  many  engineers  and  firemen  have  the  idea  that  they  are  not 
fitted  to  make  boiler  tests.  This  is  altogether  wrong.  Any  man 
who  can  weigh  water  and  coal  and  read  steam  gages  and  thermometers 
is  able  to  do  the  work  required  in  making  a  boiler  test  for  evaporation 
or  efficiency.     Such  a  test  requires  a  knowledge  of  the  following: 

1 .  The  total  weight  of  coal  used. 

2.  JThe  total  weight  of  water  fed  to  and  evaporated  by  the  boiler. 

3.  The  average  temperature  of  the  feed  water. 

4.  The  average  steam  pressure  in  the  boiler. 

If  these  four  items  are  known,  a  series  of  simple  calculations  will 
show  how  much  water  is  being  evaporated  per  pound  of  coal,  and  the 
efficiency  of  the  boiler  and  furnaqp. 

To  make  a  test,  the  following  apparatus  and  instruments  are 
necessary : 

1.  Scales  to  weigh  the  coal. 

2.  Apparatus  to  weigh  or  measure  the  feed  water. 

3.  Thermometers  to  take  feed-water  temperature. 

4.  Gages  to  indicate  steam  pressure. 

A  boiler  test  to  be  of  value  should  extend  over  a  period  of  at  least 
eight  hours.     The  longer  the  test  the  more  accurate  the  results. 

1  For  the  sake  of  simplicity,  only  the  essential  elements  of  boiler  and  furnace  testing  are  treated  in  this 
bulletin.  For  rules  covering  the  refinements  for  an  exhaustive  test,  the  reader  is  referred  to  the  boiler  test 
code  of  the  American  Society  of  Mechanical  Engineers.  Copies  of  this  code  can  be  obtained  from  the 
secretary,  29  West  Thirty-ninth  8treet,  New  York  City. 

3 


BOILER  AND  FURNACE   TESTING. 


WEIGHING  THE  COAL. 

The  weight  of  coal  used  during  a  test  may  easily  be  found  by  using 
an  ordinary  wheelbarrow  and  a  platform  scales,  arranged  as  in 
figure  1.  At  each  side  of  the  scales  build  an  incline  with  its  top  level 
with  the  top  of  the  platform,  but  take  care  not  to  have  either  one 
touch  the  platform.  Set  the  empty  wheelbarrow  on  the  scales,  run 
the  movable  weight  or  poise  out  until  it  exactly  balances  the  weight 
of  the  barrow  and  lock  it  in  position  with  the  thumbscrew. 

Next,  put  weights  on  the  scale  pan  A  to  correspond  to  a  net  weight 
of  250  or  300  pounds  of  coal.  Fill  the  barrow  with  coal,  run  it  on  the 
scales,  and  add  coal  or  take  off  coal  until  the  scales  balance.  This 
is  easily  done  by  having  a  small  pile  of  coal  B  beside  the  scales.  If 
the  weights  on  the  scale  pan  represent,  say,  300  pounds,  the  net 
weight  of  coal  in  the  barrow  is  exactly  300  pounds.     This  coal  is 


TALLY 


2  Add 'to  balance  net  weight  of  coal 
J  Settobatance  tare  of  wheelbarrow 


fWi. 


wheeled  in  front  of  the  boiler  and  dumped  on  the  clean  floor,  and 
the  barrow  is  returned  for  another  load. 

Each  time  the  barrow  of  coal  is  weighed  on  the  scales  and  taken 
to  the  boiler  being  tested,  a  tally  mark  should  be  made  on  a  board 
nailed  to  the  wall  beside  the  scales.  Each  tally  mark  represents  300 
pounds  of  coal,  since  the  amount^of  coal  in  the  barrow  is  adjusted 
at  each  weighing,  so  that  the  scales  just  balance.  At  the  end  of  the 
test,  therefore,  the  number  of  tally  marks  is  multiplied  by  300,  and 
the  product  is  the  weight  of  coal  used,  provided  it  has  all  been  fired; 
but  if  any  coal  remains  in  front  of  the  boiler  at  the  close  of  the  test, 
it  must  be  gathered  up  and  weighed,  and  its  weight  must  be  sub- 
tracted from  the  total  weight  indicated  by  the  tally  marks  to  get 
the  number  of  pounds  of  coal  actually  fired.  You  should,  of  course, 
start  the  test  with  no  coal  in  front  of  the  boiler. 

Oare  must  be  taken  not  to  forget  to  make  a  tally  mark  each  time 
a  barrow  of  coal  is  run  off  the  scales.  By  setting  the  scales  so  as  to 
show  any  net  weight,  such  as  250  or  300  pounds,  and  making  each  bar- 


BOILER  AND  FURNACE   TESTING.  5 

row  load  exactly  this  weight,  much  time  is  saved,  as  it  is  unnecessary 
to  change  any  of  the  weights  or  the  position  of  the  rider  on  the 
scale  beam. 

If  the  coal  used  in  the  test  is  to  be  analyzed,  take  a  sample  of 
from  4  to  6  pounds  from  each  barrow  and  throw  it  into  a  box  near 
the  scales  Do  this  before  the  coal  is  weighed.  These  small  amounts 
from  the  various  barrow  loads  will  then  give  a  fair  average  sample 
of  the  coal  used  during  the  test. 

The  condition  of  the  furnace  should  be  the  same  at  the  end  of  the 
test  period  as  at  the  start.  Therefore,  at  the  moment  the  test  is 
begun,  observe  the  thickness  of  the  fuel  bed  and  the  condition  of  the 
fire.  If  the  fire  was  cleaned,  say,  an  hour  before  the  test  began,  see 
that  it  is  cleaned  an  hour  before  the  time  when  the  test  is  scheduled 
to  end.  If  the  coal  was  fired,  say,  eight  minutes  before  the  test 
started,  the  last  coal  used  during  the  test  should  be  fired  eight  min- 
utes before  the  end  of  the  test.  The  object  of  these  precautions  is 
to  insure  the  same  conditions  at  start  and  finish,  as  nearly  as  pos- 
sible; otherwise,  the  coal  weighed  will  not  be  the  same  as  the  coal 

consumed. 

MEASURING  THE  FEED  WATER. 

The  quantity  of  water  fed  to  the  boiler  during  the  test  may  be 
found  by  metering  or  by  weighing.  A  reliable  water  meter  is  recom- 
mended for  this  work.  There  are  a  number  of  good  makes,  of  differ- 
ent types,  such  as: 

1.  Venturi  meter. 

2.  Weir  or  V-notch  meters. 

3.  Diaphragm  meters. 

4.  Displacement  meters. 

5.  Water  weighers. 

The  best  form  of  meter  to  use  in  any  particular  case  depends  on 
the  local  conditions  in  the  plant;  but  every  plant  should  be  provided 
with,  a  permanently  installed  meter  of  some  type.  The  displacement 
form  of  meter  should  be  used  only  with  cold  water,  however. 

If  there  is  no  meter  or  water  weigher  in  the  plant,  the  feed  water 
used  during  the  test  can  be  measured  by  the  three-barrel  arrange- 
ment illustrated  in  figure  2. 

Obtain  three  water-tight  barrels,  and  set  two  of  them  close  together 
on  a  platform  directly  over  the  third,  leaving  about  12  inches  above 
barrel  3  in  which  to  fit  the  valves  V  and  the  nipples  in  the  bottoms 
of  barrels  1  and  2.  Near  the  top  of  each  of  the  barrels  1  and  2 
screw  a  1-inch  overflow  pipe  0. 

Run  a  pipe  P  from  the  city  main  or  other  source  of  supply  above 
barrels  1  and  2,  and  put  a  valve  A  on  the  pipe  leading  to  each  barrel. 
From  barrel  3  run  a  suction  pipe  to  the  feed  pump  that  is  to  pump 
water  to  the  boiler  to  be  tested.     It  is  best  to  have  a  by-pass  from 


6 


BOILER  AND  FURNACE  TESTING. 


the  usual  water  supply  direct  to  the  feed  pump,  or  to  another  pump 
connected  to  the  boiler,  so  that  in  case  of  any  trouble  with  the  test- 
ing barrels,  the  regular  operation  of  the  boiler  may  be  resumed  with- 
out shutting  down. 

The  next  step  is  to  fill  barrels  1  and  2  with  water  until  they  over- 
flow at  O.  This  water  should  be  of  practically  the  same  average 
temperature  as  that  which  is  to  be  used  during  the  test.  Barrel  3 
should  be  high  enough  above  the  feed  pump  so  that  the  pump  will 
handle  hot  water.  Put  barrel  3  on  a  scales,  before  connecting  it  to 
the  feed  pump,  and  weigh  it.  Then  let  the  water  from  barrel  1  run 
into  barrel  3,  and  weigh  again.  The  second  weight  minus  the  first 
weight  is  the  net  weight  of  water  run  in  from  barrel  1  and  is  the 
weight  of  water  contained  in  barrel  1  when  filled  to  the  overflow. 
The  weight  of  water  in  barrel  2  when  it  is  filled  to  the  overflow  can 
be  found  in  like  manner.     Mark  these  weights  down. 


When  the  net  weights  are  found  and  barrel  3  is  removed  from  the 
scales  and  connected  to  the  feed  pump,  the  apparatus  is  ready  to 
begin  the  test.  Start  with  the  level  of  the  water  about  1  foot  below 
the  top  of  the  barrel  3,  and  drive  a  nail  into  the  barrel  to  mark  this 
level.  When  the  test  is  finished,  the  level  should  be  brought  to  the 
same  point,  so  that  the  water  that  has  passed  through  barrels  1  and  2 
will  accurately  represent  the  weight  of  water  fed  to  the  boiler  during 
the  test. 

When  the  test  is  to  begin,  stop  the  feed  pump  and  tie  a  string 
around  the  gage  glass  on  the  boiler  to  mark  the  height  of  the  water 
level  in  the  boiler.  Then  start  the  pump  connected  to  barrel  3. 
Fill  barrels  1  and  2  up  to  the  overflow  before  the  test  is  started. 
Then  open  the  valve  V  on  barrel  1  and  let  the  water  run  into  barrel  3 
as  fast  as  the  feed  pump  draws  water  from  barrel  3.  When  barrel  1 
is  emptied  close  its  valve  V  and  open  its  valve  A  so  as  to  refill  it. 


BOILER  AND  FURNACE   TESTING.  7 

While  barrel  1  is  filling  empty  barrel  2  into  barrel  3  in  the  same  way, 
and  continue  to  fill  and  empty  barrels  1  and  2  alternately.  In  this 
way  barrel  3  will  be  kept  supplied  with  water  that  has  been  measured 
in  barrels  1  and  2,  the  net  weights  of  which  were  found  before  the 
test  began.  Keep  a  separate  tally  of  the  number  of  times  each  of  the 
barrels  1  and  2  is  emptied  into  barrel  3.  At  the  end  of  the  test  the 
number  of  tallies  for  each  barrel  multiplied  by  the  weight  of  the 
water  that  barrel  will  hold  will  be  the  weight  of  water  measured  in 
that  barrel.  The  sum  of  these  weights  for  barrels  1  and  2  will  be 
the  weight  of  water  used  in  the  test. 

With  a  three-barrel  arrangement  like  this,  water  can  be  weighed 
rapidly  enough  to  supply  300  boiler  horsepower. 

Before  starting  a  test  make  sure  that  there  is  no  chance  for  water 
to  leak  into  or  out  of  the  boiler.  See  that  the  blow-off  is  tight,  that 
there  is  no  drip  from  gage  cocks,  and  that  the  feed-line  connections 
are  tight,  so  that  all  the  water  fed  to  the  boiler  will  represent  accu- 
rately the  amount  evaporated  during  the  test. 

If  a  meter  is  used  instead  of  the  three-barrel  method,  make  abso- 
lutely sure  that  the  meter  is  correct,  as  the  accuracy  of  the  test  de- 
pends on  the  accuracy  with  which  the  water  measurements  are  made. 
After  a  meter  is  installed,  test  it  to  see  that  it  operates  correctly  under 
the  'plant  conditions. 

The  water  level  in  the  boiler  should  be  the  same  at  the  end  of  the 
test  as  at  the  beginning.  As  the  time  for  stopping  the  test  draws 
near,  therefore,  try  to  bring  the  conditions  the  same  as  at  the  start. 
Do  not,  however,  run  the  feed  pump  rapidly  in  the  last  few  minutes 
for  the  test  in  order  to  obtain  the  same  water  level.  If  there  is  a 
slight  difference  in  level,  calculate  the  weight  of  water  it  represents 
and  make  the  necessary  correction  to  the  total  weight  of  water  fed. 

TEMPERATURE  OF  FEED  WATER. 

Every  plant  should  have  a  thermometer  on  the  feed  line,  so  as  to 
find  the  temperature  of  the  feed  water.  Preferably,  this  thermom- 
eter should  be  of  the  recording  type.  If  such  a  form  of  thermometer 
is  used  during  the  test,  it  is  unnecessary  to  take  the  feed  temperature 
at  stated  intervals,  as  the  record  will  show  the  varying  temperatures, 
and  so  the  average  feed  temperature  during  the  test  can  easily  be 
found. 

If  there  is  no  thermometer  in  the  feed  line,  take  the  feed-water 
temperature  by  means  of  a  thermometer  hung  in  barrel  3  (figure  2)  by 
a  hook  over  the  edge  of  the  barrel.  Read  this  thermometer  every 
half  hour  during  the  test  if  the  feed-water  temperature  is  fairly  uni- 
form; but  if  it  varies  considerably,  read  the  thermometer  every  15 
minutes.  The  object  is  to  obtain  the  average  feed-water  tempera- 
ture during  the  test  period.     Therefore,  mark  down  the  tempera- 


8  BOILER  AND  FURNACE  TESTING. 

tures  as  read  at  the  stated  intervals.  At  the  close  of  the  test  add  the 
readings  and  divide  their  sum  by  the  number  of  readings  and  yon 
will  have  the  average  temperature  of  the  feed  water. 

STEAM  PRESSURE. 

i  Every  boiler  is  fitted  with  a  steam  gage  by  which  the  pressure  is 
indicated.  It  is  important  that  the  pressure  gage  be  accurate. 
What  is  wanted  in  a  test  is  the  average  pressure  of  the  steam  in 
the  boiler,  therefore,  observe  the  pressure  at  regular  intervals,  just  as 
with  the  feed-water  temperature,  and  mark  down  these  gage  readings. 
The  sum  of  the  readings  divided  by  the  number  of  readings  taken  will 
be  the  average  steam  pressure  during  the  test. 

A  recording  steam  gage  is  best  and  makes  its  own  readings. 

WORKING  UP  THE  TEST. 

After  the  boiler  test  has  been  made,  so  as  to  find  the  weight  of  coal 
burned,  weight  of  feed  water  used,  feed-water  temperature  and  steam 
pressure,  the  efficiency,  the  horsepower,  and  the  economy  must  be 
obtained  by  calculation  from  the  test  results.  The  process  of  figuring 
the  desired  results  from  the  test  data  is  called  l  'working  up  the  test." 

To  illustrate  the  method  used  in  finding  the  efficiency,  etc.,  sup- 
pose that  the  data  obtained  from  the  test  are  as  follows : 

Length  of  test hours. .  10 

Total  weight  of  coal  fired pounds. .  5, 000 

Total  weight  of  water  evaporated do 35, 000 

Average  temperature  of  feed  water °F . .  180 

Average  steam  pressure,  gage pounds  per  square  inch . .  100 

The  efficiency  of  any  process  is  always  *  comparison,  or  ratio,  of  the 
output  to  the  input.  In  the  case  of  a  steam  boiler  the  efficiency  is  the 
percentage  of  the  heat  supplied  in  the  coal  that  is  usefully  employed 
in  making  steam.  The  output  of  the  steam  boiler  is  the  heat  repre- 
sented by  the  quantity  of  water  evaporated  by  a  pound  of  coal, 
taking  into  account  the  feed  temperature  and  the  steam  pressure, 
and  input  is  the  amount  of  heat  contained  in  a  pound  of  the  coal 
used.     The  efficiency  of  the  boiler  is  the  output  divided  by  the  input. 

The  heat  contained  in  a  pound  of  coal  is  called  the  ' 'calorific  value" 
or  "heating  value"  of  the  coal.  It  can  be  found  by  taking  a  fair 
average  sample  of  the  coal  used  during  the  test,  as  explained  in  con- 
nection with  weighing  the  coal,  and  sending  the  sample  to  a  chemist, 
who  will  make  a  calorimeter  test  to  determine  its  heating  value. 

At  the  end  of  the  test  the  sample  fuel  should  be  spread  out  on  a 
clean  floor  and  all  lumps  broken  up,  so  that  no  pieces  are  larger  than 
2  inches  maximum  diameter.  Then  the  gross  sample  should  be  very 
thoroughly  mixed  by  shoveling,  after  which  it  should  be  spread  out 
in  the  form  of  a  square  of  uniform  depth  and  quartered  down  until 


BOILER  AND  FURNACE   TESTING.  9 

a  final  average  sample  is  obtained  for  shipment  to  a  competent 
chemist,  experienced  in  fuel  analysis.  (See  Bureau  of  Mines  Tech- 
nical Paper  No.  133.) 

About  2  quarts  of  the  chemist's  sample  should  be  put  in  air-tight 
tins  or  jars  for  the  determination  of  moisture;  the  balance  of  the 
sample  (the  total  weight  of  which  should  be  from  10  to  50  pounds, 
depending  on  the  total  weight  of  coal  used  in  the  test)  may  be  packed 
in  a  wooden  box  lined  with  paper  to  prevent  splinters  from  mingling 
with  the  sample.  A  duplicate  coal  sample  should  be  kept  at  the 
plant  to  be  used  in  case  of  loss  of  the  sample  sent  to  the  chemist. 

The  Bureau  of  Mines  has  published  a  bulletin  or  pamphlet  giving 
the  analyses  and  heating  values  of  the  various  kinds  and  grades  of 
coal  from  all  parts  of  the  United  States.  (Bureau  of  Mines  Bulletin 
No.  22.)  This  bulletin  can  be  used  to  learn  the  approximate  heating 
value  of  the  coal.  Simply  find  out  what  district  the  coal  used  in 
the  test  came  from,  and  its  grade,  and  then  refer  to  the  bulletin  to 
obtain  the  heating  value  of  the  coal.  If  a  chemist  can  be  obtained 
to  make  a  heat  test,  however,  it  is  better  to  use  the  heating  value 
he  determines. 

Suppose  that  during  the  test  the  coal  used  was  run-of-mine  bitu- 
minous having  a  heating  value  of  13,500  B.  t.  u.  Every  pound  of 
coal  fired,  then,  carried  into  the  furnace  13,500  heat  units,  and  this 
value  therefore  is  the  input  to  be  used  in  calculating  the  boiler 
efficiency. 

During  the  test  5,000  pounds  of  coal  was  fired  and  35,000  pounds 
of  water  was  fed  and  evaporated.  This  means  that  35,000  ;*■  5,000  =  7 
pounds  of  water  was  evaporated  per  pound  of  coal  burned.  This  is 
the  "actual  evaporation,"  and  the  heat  required  to  evaporate  this 
7  pounds  of  water  is  the  output  to  be  used  in  calculating  the  efficiency. 

Every  fireman  knows  that  it  takes  more  coal,  and  therefore  more 
heat,  to  make  steam  with  cold  feed  water  than  with  hot  feed  water; 
also,  that  it  is  somewhat  easier  to  make  steam  at  a  low  pressure 
than  at  a  high  pressure.  So  it  is  plain  that  the  heat  required  to 
evaporate  7  pounds  of  water  into  steam  depends  on  two  things, 
namely,  (1)  the  temperature  of  the  feed  water  and  (2)  the  pressure 
of  the  steam  in  the  boiler.  From  the  data  of  the  test,  both  the  aver- 
age feed-water  temperature  and  the  average  steam  pressure  are 
known,  and  so  it  is  a  simple  matter  to  find  out  the  amount  of  heat 
needed  to  evaporate  7  pounds  of  water  from  the  average  temperature 
to  steam  at  the  average  pressure. 

A  pound  of  water  at  212°  F.  must  have  970.4  B.  t.  u.  added  to  it 
to  become  a  pound  of  steam  at  212°  F.,  or  zero  gage  pressure.  This 
value,  970.4  B.  t.  u.,  is  called  the  latent  heat  of  steam  at  atmos- 
pheric pressure,  or  the  heat  "from  and  at  212°  F."  It  is  the  heat 
required  to  change  a  pound  of  water  from  212°  F.  to  steam  at  212°  F., 
75822°— 18— —2 


10  BOILER  AND  FURNACE   TESTING. 

and  is  used  by  engineers  as  a  standard  by  which  to  ■compare  the 
evaporation  of  different  boilers. 

In  a  boiler  test  the  temperature  of  the  feed  water  is  usually  some- 
thing less  than  212°  F.,  and  the  steam  pressure  is  commonly  higher 
than  zero,  gage.  In  the  test  outlined  previously,  the  feed-water  tem- 
perature was  ISO0  F.  and  the  pressure  was  100  pounds  per  square 
inch,  gage.  It  must  be  cleaT,  then,  that  the  amount  of  heat  re- 
quired to  change  a  pound  of  water  at  180°  to  steam  at  100  pounds 
gage  pressure  is  not  the  same  as  to  make  a  pound  of  steam  from  and 
at  212°  F. 

To  make  allowance  for  the  differences  in  temperature  and  pres- 
sure, the  actual  evaporation  must  be  multiplied  by  a  number  called 
the *  factor  of  evaporation."  The  factor  of  evaporation  has  a  certain 
value  corresponding  to  every  feed-water  temperature  and  boiler  pres- 
sure, and  the  values  of  this  factor  are  given  in  the  accompanying 
table.  Along  the  top  of  the  table  are  given  the  gage  pressures  of 
the  steam.  Iri  the  columns  at  the  sides  of  the  table  are  given  the 
feed-water  temperatures.  To  find  the  factoT  of  evaporation  for  a 
given  set  of  conditions,  locate  the  gage  pressure  at  the  top  of  the 
table  and  follow  down  that  eolumn  to  the  horizontal  line  on  which 
the  feed-water  temperature  is  located.  The  value  in  this  column 
and  on  the  horizontal  line  thus  found  is  the  factor  of  evaporation 
required.  If  the  feed  water  has  a  temperature  greater  than  212°  F., 
obtain  the  proper  factor  of  evaporation  from  the  Marks  and  Davis 
steam  tables. 

Take  the  data  of  the  test,  for  example.  The  average  steam  pres- 
sure is  100  pounds,  gage.  The  average  feed-water  temperature  is 
180"°  F.  So,  in  the  table  locate  the  eolumn  headed  100  and  follow 
down  this  column  to  the  line  having  180  at  the  ends,  and  the  value 
where  the  column  and  the  line  eross  is  1.0727,  which  is  the  factor  of 
evaporation  for  a  feed-water  temperature  of  180°  F.  and  a  steam 
pressure  of  100  pounds,  gage. 

This  faetor,  1.0727,  indicates  that  to  change  a  pound  of  water  at 
180°  F.  to  steam  at  100  pounds  requires  1.0727  times  as  much  heat 
as  to  change  a  pound  of  water  at  212°  F.  to  steam  at  atmospheric 
pressure.  In  other  words,  the  heat  used  in  producing  an  actual  evap- 
oration of  7  pounds  under  the  test  conditions  would  have  evaporated 
7x1.0727=7.5  pounds  from  and  at  212°  F.  Henee,  7.5  pounds  is 
ealled  the  "equivalent  evaporation  from  and  at  212'®  F."  per  pound 
of  coal  used. 

As  already  stated,  it  takes  970.4  B.  t.  u.  to  make  a  pound  of 
steam  from  and  at  212°  F.  Then  to  make  7.5  pounds  there  wrould 
be  required  7.5  X  970.4  =  7,278  B.  t.  u.  This  is  the  amount  of  heat 
required  to  change  7.5  pounds  of  water  at  212°  F.  to  steam  at  zero 
gage  pressure,  but  it  is  also  the  heat  required  to  change  7  pounds 


BOILER  AND  FURNACE  TESTING.  11 

of  water  at  180°  F.  to  steam  at  100  pounds  gage  pressure,  because 
7.5  pounds  from  and  at  212°  F.  is  equivalent  to  7  pounds  from  180° 
F.  to  steam  at  100  pounds.  Therefore,  the  7,278  B.  t.  u.  is  the 
amount  of  heat  usefully  employed  m  making  steam  per  pound  of 
coal  fired,  and  so  it  is  the  output.  Accordingly,  the  efficiency  of  the 
boiler  is — 

Efficiency  =  ^^t  =  ^=J0.54,  nearly. 

In  other  words,  the  efficiency  of  the  boiler  is  0.54,  or  54  per  cent, 
which  means  that  only  a  little  more  than  half  of  the  heat  in  the  coal 
is  usefully  employed  in  making  steam. 

The  chart  shown  in  figure  3  is  given  to  save  the  work  of  figuring 
the  efficiency.  If  the  equivalent  evaporation  per  pound  of  coal  is 
calculated  and  the  heating  value  of  the  coal  is  known,  the  boiler 
efficiency  may  be  found  directly  from  the  chart.  At  the  left-hand 
side  locate  the  point  corresponding  to  the  equivalent  evaporation 
and  at  the  bottom  locate  the  point  corresponding  to  the  heating 
value  of  the  coal.  Follow  the  horizontal  and  vertical  lines  from 
these  two  points  until  they  cross,  and  note  the  diagonal  line  that  is 
nearest  to  the  crossing  point.  The  figures  marked  on  the  diagonal 
line  indicate  the  boiler  efficiency. 

Take  the  case  just  worked  out,  for  example.  #fne  equivalent 
evaporation  is  7.5  pounds  and  the  heating  value  of  the  fuel  is  13,500 
B.  t.  u.  At  the  left  of  the  ehart  locate  the  point  7.5  midway  between 
7  and  8  and  at  the  bottom  locate  the  point  13,500  midway  between 
13,000  and  14,000.  Then  follow  the  horizontal  and  vertical  lines 
from  these  two  points  until  they  cross,  as  indicated  by  the  dotted 
lines.  The  crossing  point  lies  on  the  diagonal  corresponding  to  54, 
and  so  the  efficiency  is  54  per  cent. 

BOILER  HORSEPOWER  OR  CAPACITY. 

The  capacity  of  a  boiler  is  usually  stated  in  boiler  horsepower.  A 
boiler  horsepower  means  the  evaporation  of  34.5  pounds  of  water 
per  hour  from  and  at  212°  F.  Therefore,  to  find  the  boiler  horse- 
power developed  during  a  test,  calcuate  the  evaporation  from  and 
at  212°  F.  per  hour  and  divide  it  by  34.5. 

Take  the  test  previously  mentioned,  for  example.  Tne  evapora- 
tion from  and  at  212°  F.  or  the  equivalent  evaporation,  was  7.5 
pounds  of  water  per  pound  of  ooaL  The  weight  of  coal  burned  per 
hour  was  5,000-^10  =  500  pounds.  Then  the  equivalent  evapora- 
tion was  7.5x500  =  3,750  pounds  per  hour.  According  to  the  fore- 
going definition  of  a  boiler  horsepower,  then — 

Boiler  horsepower  =  1^~=-=  109. 


12  BOILER  AND  FURNACE   TESTING. 

The  "rated  horsepower"  of  a  boiler,  or  the  "builders'  rating,"  ia 
the  number  of  square  feet  of  heating  surface  in  the  boiler  divided 
by  a  number.  In  the  case  of  stationary  boilers  this  number  is  10 
or  12,  but  10  is  very  commonly  taken  as  the  amount  of  heating 
surface  per  horsepower.  Assuming  this  value  and  assuming  further 
that  the  boiler  tested  had  1,500  square  feet  of  heating  surface,  its 
rated  horsepower  would  be  1,500 -r-  10=  150  boiler  horsepower. 

It  is  often  desirable  to  know  what  per  cent  of  the  rated  capacity 
is  developed  in  a  test.  This  is  found  by  dividing  the  horsepower 
developed  during  the  test  by  the  builders'  rating.  In  the  case  of 
the  boiler  tested,  109  horsepower  was  developed.  The  percentage 
of  rated  capacity  developed,  therefore,  was  109-5-150  =  0.73,  or  73 
per  cent. 

HEATING  SURFACE. 

The  heating  surface  of  a  boiler  is  the  surface  of  metal  exposed  to 
the  fire  or  hot  gases  on  one  side  and  to  water  on  the  other  side. 
Thus,  the  internal  surface  of  the  tubes  of  a  fire-tube  boiler  is  the 
heating  surface  of  the  tubes,  but  the  outside  surface  of  the  tubes  of 
a  water-tube  boiler  is  the  heating  surface  of  those  tubes.  In  addi- 
tion to  the  tubes,  all  other  surfaces  which  have  hot  gases  on  one  side 
and  water  on  the  other  must  be  taken  into  account.  For  instance, 
in  a  fire-tube  boiler  from  one-half  to  two-thirds  of  the  shell  (depend- 
ing on  how  the  boiler  is  set)  acts  as  heating  surface.  In  addition  to 
this,  the  surface  presented  by  both  heads,  below  the  water  level,  has 
to  be  computed.  The  heating  surface  of  each  head  is  equal  to  two- 
thirds  its  area  minus  the  total  area  of  the  holes  cut  away  to  receive 
the  tubes. 

COST  OF  EVAPORATION. 

The  cost  of  evaporation  is  usually  stated  as  the  cost  of  fuel  required 
to  evaporate  1,000  pounds  of  water  from  and  at  212°  F.  To  find  it, 
multiply  the  price  of  coal  per  ton  by  1,000  and  divide  the  result  by 
the  product  of  the  equivalent  evaporation  per  pound  of  coal  and  the 
number  of  pounds  in  a  ton. 

Suppose  that  the  cost  of  the  coal  used  in  the  foregoing  test  was 
$3.60  per  ton  of  2,000  pounds.  The  equivalent  evaporation  per 
pound  of  coal  was  7.5  pounds.  Therefore  the  cost  of  evaporating 
1,000  pounds  of  water  from  180°  F.  to  steam  at  100-pound  gage,  is — 

$3.60X1,000     fflno. 
7.5   X  2,000  =  $0-24'  0r  24  cents- 


BOILER  AND  FURNACE   TESTING.  13 

TABLE  OF  TEST  RESULTS. 

After  the  test  has  been  made  and  properly  worked  up,  as  here- 
tofore described,  collect  all  the  results  of  the  test  on  one  sheet,  so 
that  they  can  be  kept  in  convenient  form  for  reference  and  for  com- 
parison with  later  tests.  A  brief  form  of  arranging  the  results  is  as 
follows : 

1.  Date  of  test May  20, 1918 

2.  Duration  of  test .• hours. .  10 

3.  Weight  of  coal  used pounds..  5,000 

4.  Weight  of  water  fed  and  evaporated do 35  000 

5.  Average  steam  pressure,  gauge do 100 

6.  Average  feed-water  temperature °F. .  180 

7.  Factor  of  evaporation 1  0727 

8.  Equivalent  evaporation  from  and  at  212°  F pounds. .  37, 545 

EFFICIENCY. 

9.  Efficiency  of  boiler  and  furnace per  cent. .  54 

CAPACITY. 

10.  Boiler  horsepower  developed 109 

11.  Builders'  rated  horsepower 150 

12.  Percentage  of  rated  horsepower  developed per  cent . .  73 

ECONOMIC  RESULTS. 

13.  Actual  evaporation  per  pound  of  coal pounds..  7 

14.  Equivalent  evaporation  from  and  at  212°  F.  per  pound  of  coal  as  fired, 

pounds 7.5 

15.  Cost  of  coal  per  ton  (2,000  pounds) $3. 60 

16.  Cost  of  coal  to  evaporate  1,000  pounds  from  and  at  212°  F $0. 24 

HOW  TO  USE  THE  TEST  RESULTS. 

The  object  of  working  up  a  test  is  to  obtain  a  clear  idea  as  to  the 
efficiency  of  operation  of  the  boiler  or  its  operating  cost.  Conse- 
quently, after  the  calculations  have  been  made,  they  should  be 
used  as  a  basis  for  study  with  the  idea  of  improving  the  boiler  per- 
formance. 

Take  the  matter  of  boiler  efficiency,  for  example,  as  found  from 
the  test  mentioned.  Its  value  was  54  per  cent.  This  is  altogether 
too  low  and  indicates  wasteful  operation.  The  efficiency  of  a  hand- 
fired  boiler  ought  not  to  be  less  than  65  per  cent,  and  it  can  be  in- 
creased to  70  per  cent  by  careful  management  under  good  conditions. 

The  chart  in  figure  3  can  be  used  to  indicate  the  evaporation  that 
should  be  obtained  in  order  to  reach  a  desired  efficiency.  Suppose, 
for  example,  that  it  is  desired  to  know  how  much  water  per  pound 
of  coal  must  be  evaporated  to  produce  a  boiler  efficiency  of  65  per 
cent  with  coal  having  a  heating  value  of  13,500  B.  t.  u.  per  pound. 

L<pcate  13,500  at  the  bottom  of  the  chart,  follow  the  vertical  line 
until  it  meets  the  diagonal  marked  65  per  cent,  and  then  from  this 


14 


BOILER  AND  FURNACE   TESTING. 


point  follow  the  horizontal  line  to  the  left-hand  edge,  where  the 
figure  9  is  found.  This  means  that  the  equivalent  evaporation 
from  and  by  212°  F.  per  pound  of  coal  must  be  9  pounds  of  water. 
If  the  steam  pressure  is  100  pounds  gauge,  and  the  feed-water  tem- 
perature is  180°  F.  the  factor  of  evaporation  is  1.0727,  then  the 
actual  evaporation  must  be  9 -i- 1.0727  =  8.36  pounds  per  pound  of 


Jieating  Va/ue  of  Coa/,  in  B-t-u.^Fer  Pound 
Fig.  3. 

coal.  In  other  words,  to  increase  the  efficiency  from  54  per  cent  to 
65  per  cent  under  the  same  conditions  of  pressure  and  feed-water 
temperature,  it  would  be  necessary  to  increase  the  actual  evapora- 
tion from  7  pounds  to  8.36  pounds.  This  would  mean  practically 
20  per  cent  more  steam  from  the  same  weight  of  coal  used. 


BOILER  AND  FURNACE   TESTING.  15 

How  to  do  this  will  require  some  study  and  experimenting  on  the 
part  of  the  fireman  or  engineer.  The  three  most  common  reasons 
for  low-boiler  efficiency  are  (1)  excess  air,  (2)  dirty  heating  surfaces, 
and  (3)  loss  of  coal  through  the  grates.  The  first  of  these  items  is 
the  most  important  of  the  three.  In  most  cases  the  greatest  pre- 
ventable waste  of  coal  in  a  boiler  plant  is  directly  due  to  excess  air. 
Excess  air  simply  means  the  amount  of  air  which,  gets  into 
the  furnace  and  boiler  which  is  not  needed  for  completing  the  com- 
bustion of  the  coal.  Very  often  twice  as  much  air  is  admitted  to  the 
boiler  setting  as  is  required.  This  extra  or  excess  air  is  heated  and 
carries  heat  out  through  the  chimney  instead  of  heating  the  water 
in  the  boiler  to  make  steam.  There  are  two  ways  in  which  this 
excess  air  gets  into  the  furnace  and  boiler  setting.  First,  by  a 
combination  of  bad  regulation  of  drafts  and  firing.  The  chances 
are  your  uptake  damper  is  too  wide  open.  Try  closing  it  a  little. 
Then,  there  may  be  holes  in  the  fire.  Keep  these  covered.  The 
second  way  excess  air  occurs  is  by  leakage  through  the  boiler  setting, 
through  cracks  in  the  brickwork,  leaks  around  the  frames  and  edges 
of  cleaning  doors,  and  holes  around  the  blow-off  pipes.  There  are 
also  other  places  where  such  air  can  leak  in. 

Take  a  torch  or  candle  and  go  over  the  entire  surface  of  your 
boiler  setting — front,  back,  sides,  and  top.  Where  the  flame  of  the 
torch  is  drawn  inward  there  is  an  air  leak.  Plaster  up  all  air  leaks 
and  repair  the  -brickwork  around  door  frames  where  necessary. 
You  should  go  over  your  boiler  for  air  leaks  once  a  month. 

In  regard  to  best  methods  of  firing  soft  coal,  see  Technical  Paper 
No.  80  of  the  Bureau  of  Mines,  which  may  be  obtained  from  your 
State  Fuel  Administrator. 

Dirty  heating  surfaces  cause  low  efficiency  because  they  prevent 
the  heat  in  the  hot  gases  from  getting  through  into  the  water.  There- 
fore, keep  the  shell  and  tubes  free  of  soot  on  one  side  and  scale  on  the 
other.  Soot  may  be  removed  by  the  daily  use  of  blowers,  scrapers, 
and  cleaners.  The  problem  of  scale  and  pure  feed  water  is  a  big  one 
and  should  be  taken  up  with  proper  authorities  on  the  subject. 

There  are  many  things  that  may  be  done  to  increase  the  efficiency 
of  the  boiler  and  to  save  coal.  For  convenience  a  number  of  these 
points  are  grouped  in  the  following  list: 


16 


BOILER  AND  FURNACE  TESTING. 


WHAT  TO  DO. 

1.  Close  up  all  leaks  in  the  boiler  setting. 

2.  Keep  shell  and  tubes  free  from  soot 

and  scale. 

3.  Use  grates  suited  to  the  fuel  to  be 

burned. 

4.  Fire  often,  and  little  at  a  tune. 

5.  Cover  all  thin  spots  and  keep  fire  bed 

level. 

6.  Do  not  allow  clinkers  to  form  on  side 

or  bridge  walls. 

7.  Keep  the  ash  pit  free  from  ashes  and 

hot  clinkers. 

8.  Do  not  stir  the  fire  except  when  nec- 

essary. 

9.  Use  damper  and  not  ash-pit  doors  to 

control  draft. 

10.  See  that  steam  pipes  and  valves  are 

tight. 

11.  Keep  blow-off  valves  tight. 

12.  Cover  steam  pipes  and  the  tops  of 

boilers. 


WHY. 

To  prevent  waste  of  heat  due  to  excess 

air  admitted. 
To  allow  the  heat  to  pass  easily  into  the 

water. 
To  prevent  loss  of  unburnt  coal  through 

air  spaces. 
To  obtain  uniform  conditions  and  better 

combustion. 
To  prevent  burning  holes  in  bed  and  ad- 
mitting excess  air. 
Because  they  reduce  the  effective  area  of 

the  grate. 
To  prevent  warping  and  burning  out  of 

the  grates. 
Because  stirring  causes  clinker  and  is 

likely  to  waste  coal. 
Because  less  excess  air  is  admitted  by  so 

doing. 
Because   steam    leaks   waste    heat   and 

therefore  coal. 
Because  leaks  of  hot  water  waste  coal. 
To  prevent  radiation  and  loss  of  heat. 


Make  a  boiler  test  under  the  conditions  of  operation  as  they  now 
exist  in  your  plant.  Then  make  all  possible  improvements  as  sug- 
gested in  this  bulletin,  make  another  test  afterwards  and  note  the 
increase  in  the  equivalent  evaporation  per  pound  of  coal  used. 

Remember  that  the  firing  line  in  the  boiler  room  can  be  just  as 
patriotic  and  helpful  as  the  firing  line  at  the  front. 


BOILER  AND  FURNACE  TESTING. 
Table  of  factors  of  evaporation. 


17 


Feed  temperature, 

Steam  pressure  In  pounds  per  square  inch,  gauge. 

30 

50 

70 

80 

90 

WO 

110 

120 

1.2073 
1.2042 
1.2011 
1.1980 
1. 1949 
1. 1918 
1.1887 
1.1856 
1.  1825 
1. 1794 
1.1763 
1. 1733 
1. 1702 
1.1671 
1. 1640 
1.1609 
1. 1578 
1. 1548 
1.1518 
1.1486 
1.1455 
1.1424 
1.1393 
1.1363 
1.1332 
1.1301 
1. 1270 
1. 1239 
1.1209 
1. 1178 
1. 1147 
1. 1116 
1.1085 
1.1054 
1. 1023 
1.0993 
1.0962 
1.0931 
1.0900 
1.0869 
1.0838 
1.0807 
1.0776 
1.0745 
1.0715 
1.0684 
1.0653 
1.0632 
1.0611 
1.0591 
1.O570 
1.0549 
1.0529 
1.0508 
1.0488 
1. 0467 
1.0446 
1.0425 
1.0405 
1.03S4 
1.0363 
1.0343 
1,0322 
1.0301 
1.02S1 
1.0260 
1.0239 
1.0218 

1.2144 
1.2113 
1.2082 
1.2051 
1.2020 
1.1989 
1.1958 
1. 1927 
1. 1896 
1.1865 
1.1835 
1.1804 
1. 1773 
1.1742 
1. 1711 
1.1680 
1.1650 
1. 1619 
1.1588 
1. 1557 
1. 1526 
1. 1495 
1.1465 
1.1434 
1.1403 
1. 1372 
1. 1341 
1. 1310 
1.1280 
1. 1249 
1.1218 
1. 1187 
1.1156 
1. 1125 
1.1095 
1.1064 
1.1033 
1.1002 
1.0971 
1.0940 
1.0909 
1.0878 
1.0847 
L0817 
1.0786 
1.0755 
1.0724 
1.0703 
1.0683 
1.0662 
1.0641 
1.0621 
1.O609 
1.0579 
1.0559 
1.0538 
1.0517 
1.0497 
1.0476 
1.0455 
1.0435 
1.0414 
1.0393 
1.0372 
1.0352 
1.0331 
1.0310 
1.0290 

L2195 
L2164 
1.2133 
L2102 
1.2071 
1.2040 
L2009 
1.1978 
1. 1947 
1.1916 
1.1885 
1.1854 
1.1823 
1.1792 
1. 1762 
1. 1731 
1.1700 
1. 1669 
1.1638 
1.1608 
1. 1577 
1.1546 
1. 1515 
1. 1484 
1.1453 
1. 1423 
1.1392 
1. 1360 
1. 1330 
1.1299 
1.1269 
1. 1238 
1.1207 
1.1178 
1. 1145 
1.1114 
1.1083 
1.1052 
1.1022 
1.0991 
1.0960 
1.0929 
1.0898 
1.0867 
1.0836 
1.0805 
1.0774 
1.0754 
1.0733 
1.0712 
1.0692 
1.0671 
1.0650 
1.0630 
1.0609 
1.058S 
1.0568 
1.0547 
1.0528 
1.0506 
1.0485 
1.0464 
1.0444 
1.0423 
1.0402 
1.0381 
1.0361 
1.0340 

L2216 
1.2184 
1.2153 
L2122 
1.2091 
1.2060 
1.2029 
1.1998 
L1967 
1.1937 
L1908 
1.1875 
1.1844 
1.1813 
1.1782 
L1751 
L1721 
1.1690 
1.1659 
1.1628 
1. 1597 
1.1566 
1.1536 
1.1505 
1. 1474 
1.1443 
1. 1412 
1. 1382 
1. 1351 
1.1320 
1. 1289 
1.1258 
1.1227 
1.1197 
1.1166 
1.1135 
1.1104 
1. 1073 
1. 1042 
1. 1011 
1.0980 
1.O950 
1.0919 
1.0888 
1.0857 
1.0826 
1.0795 
1.0774 
1.0754 
1.0733 
1.0712 
1.0692 
1.0671 
LO650 
1.0630 
1.0609 
1.0588 
1.0568 
1.0547 
1.0526 
1.0508 
1.0485 
1.0464 
1.0444 
1.0423 
1.0102 
1.0381 
1.0361 

1.2234 
1.2203 
1.2172 
1.2141 
1.2110 
1.2079 
1.2048 
L2017 
L1986 
L1955 
L1924 
L1893 
L1862 
1.1832 
L1S01 
L1770 
1.1739 
1.1708 
L1678 
L1647 

i.  it; ir. 

L1585 
1.1554 
1.1523 
1. 1492 
1.1462 
1. 1431 
1.1400 
L1369 
1. 1339 
1.1308 
1. 1277 
1. 1246 
1. 1215 
1.1184 
1.1153 
1.1123 
1.1092 
1.1061 
1. 1030 
1.0999 
1.0968 
1.0937 
1.0908 
1.0875 
1.0844 
1.0813 
1.0793 
1.0772 
1.0752 
1.0731 
1.0710 
1.0699 
1.0669 
1.0648 
1.0628 
L0607 
1.0588 
1.0566 
1.0545 
1.0524 
1.0504 
1.0483 
1.0462 
1.0441 
1. 0421 
1.0400 
1.0379 

L  22.51 
1.2219 
1.2188 
L2157 
L2126 
1.2095 
1.2064 
1.2033 
1.2002 
1.1972 
L1941 
L191Q 
1.1879 
L1848 
L1817 
L1786 
L1756 
1.1725 
1. 1694 
1.1663 
1.1632 
1.1602 
1.1571 
1.1540 
1.1509 
1. 1478 
L1447 
1. 1417 
1.1386 
1.1355 
3L1324 
1.1293 
1.1262 
1. 1232 
1.1201 
1.1179 
1.1139 
1.1108 
1. 1077 
1. 1046 
1. 1015 
1.0985 
1.0954 
1.092J 
1.0892 
1.0861 
1.0839 
1.0809 
1.0789 
1.0768 
1.0747 
1.0727 
1.0708 
1.0685 
1.0665 
1.0644 
1.062* 
1.0603 
1.0&J 
1.0561 
1.0541 
1.0520 
1.0499 
1.0479 
1.0458 
1.0437 
1.0416 
1.0398 

1.2266 
1.2235 
1.2204 
L2173 
1.2142 
L2111 
L2080 
1.2049 
1.2018 
1.1987 
1.1956 
L1925 
1.1894 
1.1864 
L1833 
L1802 
L1771 
L1740 
L1710 
L1679 
L1048 
L1617 
1.  list! 
1.1555 
1.1525 
1.1494 
1.1463 
1. 1432 
1.1401 
1.1370 
L1340 
1.1309 
L1278 
1.1247 
1. 1216 
1.1185 
1.1154 
1.1124 
1.1093 
1.  W62 
1. 1031 
1.  WOO 
1.0969 
1.0938 
1.0907 
L0876 
1.0845 
1.0825 
1.0804 
L0783 
1.0763 
1.0742 
1.0721 
L0701 
1.0680 
1.0660 
L0639 
1.0618 
1.0597 
1.0577 
1.0556 
1.0535 
1.0515 
1.0494 
1.0473 
L0453 
1.0432 
1.0411 

J.  2279 

1.2248 

1.2217 

1.2180 

1.2155 

1.2124 

1.2093 

1.2082 

1.2031 

1.2000 

1.1970 

1.1939 

1.1908 

1.1877 

1.1646 

1.1815 
1.1785 

1.1754 
1.1723 

1.1892 

1.1881 

1.1680 

1.1800 

1.1509 
1.1538 
1.1507 
1. 1476 
1. 1445 

1.1415 

122 

1.1384 
1.1353 
1.1382 

l.uw 

1.1960 

11230 

1.  1199 

1.1168 

1.1187 

1.1106 

1.1075 

1.1044 

1. 1013 

1.0982 

1. 0691 

1   i<921 

L  S 

1.0838 

1.0817 

1.0797 

1.0778 

1.0758 

1.0735 

1.0714 

l.ms 
1.0652 
1.0632 
1.0611 
i  Ml 
1.0570 
1.0549 
1. 0528 
1.0507 
1.0487 
1.0486 
1.0445 
1.0425 

196 

198. 

tm  ..        

204  

M6  

90S      

no 

212 

18 


BOILER  AND  FURNACE   TESTING. 
Table  of  factors  of  evaporation — Concluded. 


Feed  temperature, 

Steam  pressure 

in  pounds  per  square  inch,  gauge. 

130 

140 

150 

160 

170 

180 

190 

200 

32 

1.2292 
1.2261 
1.2230 
1.2199 
1.2168 
1.2137 
1.2106 
1.2075 
1.2044 
1.2013 
1. 1982 
1.1951 
1. 1920 
1.1889 
1.1859 
1.1828 
1. 1797 
1.1766 
1.1735 
1.1704 
1. 1674 
1.1643 
1. 1612 
1. 1581 
1.1550 
1. 1519 
1.1489 
1.1458 
1.1427 
1.1396 
1.1365 
1.1335 
1.1304 
1. 1273 
1.1242 
1. 1211 
1.1180 
1.1149 
1.1119 
1.1088 
1.1057 
1.1026 
1.0995 
1.0964 
1.0933 
1.0902 
1.0871 
1.0850 
1.0830 
1.0809 
1.0789 
1.0768 
1.0747 
1. 0727 
1.0706 
1.0685 
1.0665 
1.0644 
1.0623 
1.0603 
1.0582 
1.0561 
1.0541 
1.0520 
1.0499 
1.0478 
1.0458 
1.0437 

1.2304 
1.2273 
1.2242 
1.2211 
1.2180 
1.2149 
1.2118 
1.2087 
1.2056 
1.2025 
1.1994 
1.1963 
1.1933 
1.1902 
1. 1871 
1.1840 
1.1809 
1. 1778 
1. 1748 
1. 1717 
1.1686 
1.1655 
1.1624 
1. 1593 
1.1563 
1.1532 
1.1501 
1. 1470 
1.1439 
1.1409 
1. 1378 
1.1347 
1. 1316 
1.1285 
1.1254 
1.1224 
1.1193 
1.1162 
1. 1131 
1.1100 
1.1069 
1.1038 
1.1007 
1.0976 
1.0945 
1.0914 
1.0883 
1.0863 
1.0842 
1.0822 
1.0801 
1.0780 
1.0760 
1.0739 
1.0718 
1.0698 
1.0677 
1.0656 
1.0636 
1.0615 
1.0594 
1.0574 
1.0553 
1.0532 
1. 0511 
1.0491 
1.0470 
1.0449 

1.2315 
1.2283 
1.2252 
1.2221 
1.2190 
1. 2159 
1.2128 
1.2097 
1.2066 
1.2035 
1.2005 
1. 1974 
1.1943 
1. 1912 
1.1881 
1.1850 
1.1820 
1.1789 
1. 1758 
1. 1727 
1.1696 
1.1665 
1.1635 
1.1604 
1.1573 
1.1542 
1.1511 
1.1481 
1.1450 
1. 1419 
1.1388 
1.1357 
1. 1326 
1.1295 
1.1265 
1.1234 
1.1203 
1. 1172 
1. 1141 
1.1110 
1. 1079 
1.1048 
1.1018 
1.0987 
1.0956 
1.0925 
1.0894 
1.0873 
1.0853 
1.0832 
1.0811 
1.0791 
1.0770 
1.0749 
1.0729 
1.0708 
1.0687 
1.0667 
1.0646 
1.0625 
1.0605 
1.0584 
1.0563 
1.0542 
1.0522 
1.0501 
1.0480 
1.0460 

1.2324 
1.2293 
1.2262 
1.2231 
1.2200 
1.2168 
1. 2137 
1. 2107 
1.2076 
1.2045 
1.2014 
1.1983 
1.1952 
1.1921 
1.1890 
1.1860 
1.1829 
1. 1798 
1.1767 
1.1736 
1.1705 
1. 1675 
1.1644 
1. 1613 
1.1582 
1.1551 
1. 1521 
1.1490 
1.1459 
1. 1428 
1. 1397 
1.1366 
1.1336 
•     1. 1305 
1. 1274 
1.1243 
1. 1212 
1.1181 
1.1150 
1. 1120 
1.1089 
1.1058 
1. 1027 
1.0996 
1.0965 
1.0934 
1.0903 
1.0882 
1.0862 
1.0841 
1.0820 
1.0800 
1.0779 
1.0759 
1.0738 
1.0717 
1.0697 
1.0676 
1.0655 
1.0635 
1.0614 
1.0593 
1. 0572 
1.0552 
1.0531 
1.0510 
1.0490 
1.0469 

1.2333 
1.2302 
1.2271 
1.2240 
1.2209 
1.2178 
1.2147 
1.2116 
1.2085 
1.2054 
1.2023 
1.1992 
1.1961 
1. 1931 
1.1900 
1.1869 
1.1838 
1.1807 
1. 1776 
1.1746 
1. 1715 
1.1684 
1.1653 
1.1622 
1.1592 
1.1561 
1.1530 
1. 1499 
1. 1468 
1. 1437 
1. 1407 
1. 1376 
1. 1345 
1. 1314 
1.1283 
1. 1252 
1. 1221 
1.1191 
1. 1160 
1.1129 
1.1098 
1.1067 
1.1036 
1.1005 
1.0974 
1.0943 
1.0912 
1.0892 
1. 0871 
1.0850 
1.0830 
1.0809 
1.0788 
1. 0768 
1.0747 
1.0727 
1.0706 
1.0685 
1.0664 
1.0644 
1.0623 
1.0602 
1.0582 
1.0561 
1.0540 
1.0520 
1.0499 
1.0478 

1.2342 
1.2311 
1.2280 
1.2249 
1. 2218 
1.2187 
1.2156 
1.2125 
1.2094 
1.2063 
1.2032 
1.2002 
1. 1971 
1.1940 
1.1909 
1. 1878 
1.1847 
1.1817 
1.1786 
1.1755 
1.1724 
1. 1693 
1.1662 
1.1632 
1.1601 
1. 1570 
1.1539 
1.1508 
1.1478 
1.1447 
1.1416 
1.1385 
1.1354 
1.1323 
1.1292 
1. 1262 
1.1231 
1. 1200 
1. 1169 
1.1138 
1.1107 
1. 1076 
1.1045 
1. 1014 
1.0984 
1.0953 
1.0922 
1.0901 
1.0880 
1.0860 
1.0839 
1.0818 
1.0798 
1.0777 
1.0756 
1.0736 
1.0715 
1.0694 
1.0674 
1.0653 
.  1.0632 
1.0612 
1.0591 
1.0570 
1.0550 
1.0529 
1.0508 
1.0487 

1.2351 
1.2320 
1.2288 
1.2257 
1.2226 
1.2195 
1.2164 
1.2133 
1.2102 
1.2072 
1.2041 
1.2010 
1. 1979 
1.1948 
1. 1917 
1.1886 
1.1856 
1.1825 
1. 1794 
1.1763 
1. 1732 
1.1701 
1. 1671 
1.1640 
1.1609 
1. 1578 
1.1547 
1. 1515 
1.1486 
1. 1455 
1. 1424 
1.1393 
1. 1362 
1.1332 
1. 1301 
1. 1270 
.      1. 1239 
1.1208 
1.1177 
1.1146 
1.1115 
1.1085 
1.1054 
1.1023 
1.0992 
1.0961 
1.0930 
1.0909 
1.0889 
1.0868 
1.0847 
1.0827 
1.0806 
1.0785 
1.0765 
1.0744 
1.0723 
1.0703 
1.0682 
1.0661 
1.0641 
1.0620 
1.0599 
1.0579 
1.0558 
1.0537 
1.0516 
1.0496 

1.2358 
1.2327 
1.2296 
1.2265 
1.2234 
1.2202 
1.2171 
1. 214i 
12110 
1. 2079 
1.2048 
1.2017 
1.1986 
1. 1955 
1.1924 
1.1894 
1.1863 
1.1832 
1.1801 
1. 1770 
1.1739 
1.1709 
1. 1678 
1.1647 
1.1616 
1. 1585 
1.1555 
1. 1524 
1.1493 
1.1462 
1. 1431 
1.1400 
1.1370 
1.1339 
1.1308 
1. 1277 
1.1246 
1. 1215 
1.1184 
1.1154 
1.1123 
1.1092 
1.1061 
1.1030 
1.0999 
1.0968 
1.0937 
1.0916 
1.0896 
1  0875 

35 

38 

41 

44 

47 

50 

53 

56 

59 

62 

65 

68 

71 

74 

77 

80 

83 

86 

89 

92 

95     

98 ' 

101 

104 

107 

110 

113 

116       

119          

122          

125              

128                  

131 

134     

137.                  

140 

143 

146..   ... 

149..             

152 

155              

158 

161 

164 

167 

170 

172 

174 

176.              

178.              

1.1854 

180.              

1.0834 

182 

1.0813 

184 

1.0793 

186 

1. 0772 

188 

1. 0751 

190 

1.0731 

192 

1.0710 

194 

1.0689 

196 

1.0669 

198 

1.0648 

200 

1.0627 

202 

1.0606 

204 \ 

1.0586 

206 

1.0565 

208 

1.0544 

210 

1.0524 

212 

1.0503 

BOILER  AND  FURNACE  TESTING.  19 

PUBLICATIONS  ON  THK  UTILIZATION  OF  COAL  AND  LIGNITE. 

A  limited  supply  of  the  following  publications  of  the  Bureau  of 
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The  Bureau  of  Mines  issues  a  list  showing  all  its  publications 
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PUBLICATIONS  AVAILABLE  FOR  FREE  DISTRIBUTION. 

Bulletin  58.  Fuel  briqueiting  investigations,  July,  1904,  to  July,  1912,  by  0.  A. 
Wright.    1913.     277  pp.,  21  pis.,  3  figs. 

Bulletin  76.  United  States  coals  available  for  export  trade,  by  Van.  H.  Man- 
ning.   1914.     15  pp.,  1  pi. 

Bulletin  85.  Analyses  of  mine  and  car  samples  of  coal  collected  in  the  fiscal 
years  1911  to  1913,  by  A.  C.  Fieldner,  H.  I.  Smith,  A.  H.  Fay,  and  Samuel  Sandford. 

1914.  444  pp.,  2  figs. 

Bulletin  89.  Economic  methods  of  utilizing  western  lignites,  by  E.  J.  Bab  cock. 

1915.  74  pp.,  5  pis.,  5  figs. 

Bulletin  119.  Analyses  of  coals  purchased  by  the  Government  during  the  fiscal 
years  1908-1915,  by  G.  S.  Pope.    1916.     118  pp. 

Bulletin  135.  Combustion  of  coal  and  design  of  furnaces,  by  Henry  Kreisinger, 
0.  E.  Augustine,  and  F.  K.  Ovitz.     1917.     144  pp.,  1  pi.,  45  figs. 

Bulletin  136.  Deterioration  in  the  heating  value  of  coal  daring  storage,  by  H.  G. 
Porter  and  F.  K.  Ovitz.    1917.    38  pp.,  7  pfe. 

Bulletin  138.  Coking  of  Illinois  coate,  by  F.  K.  Ovitz.    1917.    71  pp.,  11  pis., 

lfig. 

Technical  Paper  34.  Experiments  with  furnaces  for  a  hand-fired  return  tubular 
boiler,  by  S.  B.  Flagg,  G.  C.  Cook,  and  F.  E.  Woodman.     1914.    32  pp.,  1  pi.,  4  figs. 

Technical  Paper  50.  Metallurgical  coke,  by  A.  W.  Belden.  1913.  48  pp.,  1  pi., 
23  figs. 

Technical  Papeb  76.  Notes  on  the  sampling  and  analysis  of  coal,  by  A.  C. 
Fieldner.    1914.    59  pp.,  6  figs. 

Technical  Paper  80.  Hand-firing  soft  coal  under  power-plant  boilers,  by  Henry 
Kreisinger.     1915.    83  pp.,  32  figs. 

Technical  Papek  97.  Saving  fuel  in  heating  a  house,  by  L.  P.  Breckenridge  and 
S.  B.  Flagg.     1915.    35  pp.,  3  figs. 

Technical  Papek  98.  Effect  of  low-temperature  oxidation  on  the  hydrogen  in 
coal  and  the  change  of  weight  of  coal  in  drying,  by  S.  H.  Kata  and  H.  C.  Porter. 
1917.    16  pp.,  2  figs. 

Technical  Paper  123.  Notes  on  the  uses  of  low-grade  fuel  in  Europe,  by  R.  H. 
Fernald.     1915.    37  pp.,  4  pis.,  4  figs. 

Technical  Paper  133.  Directions  for  sampling  coal  for  shipment  or  delivery,  by 
G.  S.  Pope.     1917.     15  pp.,  1  pi. 

Technical  Paper  137.  Combustion  in  the  fuel  bed  of  hand-fired  furnaces,  by 
Henry  Kreisinger,  F.  K.  Ovitz,  and  C.  E.  Augustine.  1916.  76  pp.,  2  pb.,  21  figp. 
15  cents. 


20  BOILER  AND  FURNACE   TESTING. 

Technical  Paper  148.  The  determination  of  moisture  in  coke,  by  A.  C.  Fieldner 
and  W.  A.  Selvig.    1917.    13  pp. 

Technical:  Paper  170.  The  diffusion  of  oxygen  through  stored  coal,  by  S.  H. 
Katz.     1917.     49  pp.,  1  pi.,  27  figs. 

Technical  Paper  172.  Effects  of  moisture  on  the  spontaneous  heating  of  stored 
coal,  by  S.  H.  Katz  and  H.  C.  Porter.     1917.    25  pp.,  1  pi.,  8  figs. 

PUBLICATIONS   THAT  MAY   BE   OBTAINED   ONLY   THROUGH  THE   SUPER- 
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Bulletin  8.  The  flow  of  heat  through  furnace  walls,  by  W.  T.  Ray  and  Henry 
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Bulletin  11.  The  purchase  of  coal  by  the  Government  under  specifications, 
with  analyses  of  coal  delivered  for  the  fiscal  year  1908-9,  by  G.  S.  Pope.  1910.  80  pp. 
10  cents. 

Bulletin  13.  Resume  of  producer-gas  investigations,  October  1,  1904,  to  June  30, 
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Bulletin  14.  Briquetting  tests  of  lignite  at  Pittsburgh,  Pa.,  1908-9,  with  a  chapter 
on  sulphite-pitch  binder,  by  C.  L.  Wright.     1911.    64  pp.,  11  pis.,  4  figs.     15  cents. 

Bulletin  18.  The  transmission  of  heat  into  steam  boilers,  by  Henry  Kreisinger 
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Bulletin  21.  The  significance  of  drafts  in  steam-boiler  practice,  by  W.  T.  Ray 
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Bulletin  22.  Analyses  of  coals  in  the  United  States,  with  descriptions  of  mine 
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Ray.     1912.    380  pp.,  2  pis.,  94  figs.    50  cents. 

Bulletin  27.  Tests  of  coal  and  briquets  as  fuel  for  house-heating  boilers,  by  D.  T. 
Randall.     44  pp.,  3  pis.,  2  figs.     10  cents. 

Bulletin  37.  Comparative  tests  of  run-of-mine  and  briquetted  coal  on  locomo- 
tives, including  torpedo-boat  tests,  and  some  foreign  specifications  for  briquetted 
fuel,  by  W.  F.  M.  Goss.     1911.    58  pp.,  4  pis.,  35  figs.     15  cents. 

Bulletin  40.  The  smokeless  combustion  of  coal  in  boiler  furnaces,  with  a  chapter 
on  central  heating  plants,  by  D.  T.  Randall  and  H.  W.  Weeks.  1912.  188  pp., 
40  figs.    20  cents. 

Bulletin  41.  Government  coal  purchases  under  specifications,  with  analyses, 
for  the  fiscal  year  1909-10  by  G.  S.  Pope,  with  a  chapter  on  the  fuel-inspection  labora- 
tory of  the  Bureau  of  Mines,  by  J.  D.  Davis.     1912.    97  pp.,  3  pis.,  9  figs.     15  cents. 

Bulletin  109.  Operating  details  of  gas  producers,  by  R.  H.  Fernald.  1916. 
74  pp.     10  cents. 

Bulletin  116.  Methods  of  sampling  delivered  coal,  and  specifications  for  the 
purchase  of  coal  for  the  Government,  by  G.  S.  Pope.  1916.  64  pp.,  5  pis.,  2  figs. 
15  cents. 

Technical  Paper  20.  The  slagging  type  of  gas  producer,  with  a  brief  report  of 
preliminary  tests,  by  C.  D.  Smith.     1912.     14  pp.,  1  pi.    5  cents. 

Technical  Paper  63.  Factors  governing  the  combustion  of  coal  in  boiler  fur- 
naces; a  preliminary  report,  by  J.  K.  Clement,  J.  C.  W.  Frazer,  and  C.  E.  Augustine. 
1914.    46  pp.,  26  figs.     10  cents. 

Technical  Paper  65.  A  study  of  the  oxidation  of  coal,  by  H.  C.  Porter.  1914. 
30  pp.,  12  figs.    5  cents. 

Technical  Paper  114.  Heat  transmission  through  boiler  tubes,  by  Henry  Kreis- 
inger and  F.  K.  Ovitz.     1915.    36  pp.,  23  figs.     10  cents. 

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